The present invention relates to a moter driven mechanism for opening and closing a door, in particular, to a mechanism wich can be operated remotely from the door.
Several devices are available which use an electric motor to control the opening and closing of a door to a room. Devices are also available for which the opening or closing cycle can be initiated from a remote location using an infrared transmitter and the like such as disclosed in U.S. Pat. No. 5,040,331. Such door controlling devices must be constructed so that they do not suffer damage when the door is manually opened or closed. Similarly, they must be constructed so they do not to suffer damage when an object such as a chair blocks movement of the door during an opening or closing cycle.
Currently available door controlling devices utilize a slip clutch or the like which create a drag or resistance when the door is manually opened or closed. Such slip clutches do not terminate the door opening or closing cycle when the movement of the door is interrupted by contact with an item such as a chair or a person""s hand and, as a result, such devices apply a force against the obstruction until the operating cycle is completed. It is, therefore, desirable to provide a door controlling device which can be operated remotely to open and close a door, which will not create resistance when the door is not manually opened or closed, and for which the opening or closing cycle will terminate when the door encounters an obstruction which prevents completion of the opening or closing cycle.
The present invention is embodied in a door controlling device for opening and closing a door in a wall. The device has a linkage having a first arm, one end of which is pivotally mounted by a pin to a bracket attached to the wall and the other end of which is pivotally attached to the second end of a second arm. The first end of the second arm is pivotally attached by a second pin to a second bracket mounted to the top of a door. The drive system for the device rotates one of the arms about the pin which joins the arm to its associated bracket to open or close the door.
The device includes a drive member which is connected by a gear train to a motor and which rotates about the pivot pin in one of the brackets. As the drive member turns around the pin it will engage the associated arm and force the arm to rotate through an open cycle or a close cycle. When the devise is not in use the drive member is in a stand-by position where it will not interfere with the movement of the arm while the door is being opened or closed. When the device is called upon to carry out a door open cycle, the motor and gear train rotate the drive member in one direction about the pivot pin and push the arm attached thereto to open the door. After the door has reached the fully open position, the motor will reverse direction and return the drive member to the stand-by position. When the devise is called upon to carry out a door close cycle, the motor and drive train will rotate the drive member in the opposite direction from the door open cycle, and after the door has reached the fully closed position, the motor will again reverse direction and return the drive member to the stand-by position.
The invention also includes a start means such as a switch or an infrared transmitter and receiver for starting an open cycle or a close cycle, a current measuring device for determining whether the motor is drawing an excessive amount of electric current, a door open detector for generating a signal when the door is in a fully opened position, a door closed detector for generating a signal when the door is in a fully closed position, and a stand-by detector for detecting when the drive member has returned to the stand-by condition. A control means, which is typically a computer, responds to the start means, the current measuring means, the door open detector, and the door closed detector, and the stand-by detector for directing current to the electric motor upon receipt of a signal from the start means, for reversing power to the motor to thereby reverse the direction of the motor upon receipt of a signal from the current measuring means, the door open detector or the door closed detector, and for terminating power to the motor on receipt of a signal from the stand-by detector.
The devise is entirely disengaged when the drive member is in the standby condition. When the device is carrying out a door open or a door close cycle, and the moving door contacts a foreign object such as a chair or a person""s hand, the current measuring means will detect an increase in the current drawn by the electric motor in response to the resistance caused by the foreign object, and the control means will reverse the power to the electric motor and return the drive member to the stand-by position.